WASHINGTON • Flexing its new strength, the Supreme Court’s conservative majority Thursday cut back on a landmark voting rights law in a decision likely to help Republican states fight challenges to voting restrictions they’ve put in place following last year’s elections.

The court’s 6-3 ruling upheld voting limits in Arizona that a lower court had found discriminatory under the federal Voting Rights Act.

It was the high court’s second major decision in eight years that civil rights groups and liberal dissenting justices say weakened the Civil Rights-era law that was intended to eradicate discrimination in voting.

The decision fueled new calls from Democrats to pass federal legislation, blocked by Senate Republicans, that would counter the new state laws.

Some lawmakers and liberal groups also favor Supreme Court changes that include expanding the nine-justice bench.

“The court’s decision, harmful as it is, does not limit Congress’ ability to repair the damage done today: it puts the burden back on Congress to restore the Voting Rights Act to its intended strength,” President Joe Biden said in a statement.

Republicans argue that the state restrictions are simply efforts to fight potential voting fraud and ensure election integrity.

Biden’s Justice Department had taken the position that the Arizona measures did not violate the Voting Rights Act, but favored a narrower ruling than the one handed down Thursday.

Justice Amy Coney Barrett’s confirmation last year to replace the late Justice Ruth Bader Ginsburg entrenched the right’s dominance on a court that now has three appointees of former President Donald Trump.

In an opinion by Justice Samuel Alito, the court reversed an appellate ruling in deciding that Arizona’s regulations on who can return early ballots for another person and on refusing to count ballots cast in the wrong precinct are not racially discriminatory.

The federal appeals court in San Francisco had held that the measures disproportionately affected Black, Hispanic and Native American voters in violation of a part of the Voting Rights Act known as Section 2.

Alito wrote for the conservative majority that the state’s interest in the integrity of elections justified the measures and that voters faced “modest burdens” at most.

The court rejected the idea that showing a state law disproportionately affects minority voters is enough to prove a violation of law.

In a scathing dissent, Justice Elena Kagan wrote that the court was weakening the federal voting rights law for the second time in eight years.

“What is tragic here is that the Court has (yet again) rewritten — in order to weaken — a statute that stands as a monument to America’s greatness, and protects against its basest impulses. What is tragic is that the Court has damaged a statute designed to bring about ‘the end of discrimination in voting.’

I respectfully dissent,” Kagan wrote, joined by the other two liberal justices. Native Americans who have to travel long distances to put their ballots in the mail were most likely to be affected by Arizona’s ballot collection law.

Votes cast by Black and Hispanic voters were most likely to be tossed out because they were cast in a wrong precinct, the appeals court found.

The Supreme Court in Washington.